VERTEX piston kit for BETA RK 6, ST 50 from 1996 to 1997

VERTEX offers this piston kit for BETA RK 6, ST 50 from 1996 to 1997. The piston slides in the cylinder and takes the force of the air-fuel combustion, passing it to the connecting rod and crankshaft.

Why choose a cast piston?

A cast piston is made by pouring liquid aluminium into a mould: it is what most manufacturers fit as standard, especially on two-strokes.

• High-silicon alloy: it expands little, is fitted with tight clearance and stays quiet when cold.
• Good wear resistance of the skirt and ring grooves.
• Lower price than a forged piston, for OEM quality in normal use.
• Limit: less tolerant of overheating and highly tuned engines.

Why choose VERTEX?

Vertex has made its pistons in Italy since 1953 and has supplied KTM’s original pistons since 1996: molybdenum-disulphide coated skirt and Japanese rings. Its two-stroke pistons are cast from an 18 % silicon alloy.

When should you replace the piston on your BETA ST 50?

Harder starting, loss of power, blue smoke, oil consumption or a knock when cold: these are the signs of a tired top end.

No manufacturer hour figure for this model. Cross-Mania guideline: compression check every 15 h in hard use and every 30 h for leisure.

Specifications and fitting tips

• Bore: 39.50 mm
• Displacement: 50 cm³
• Piston diameter: 39.47 mm
• Piston material: Aluminium alloy, Cast
• Ring material: Nitride coating

Cross-Mania tip: Measure the cylinder bore before ordering: the piston must match your cylinder size. Follow the manufacturer's break-in procedure and replace the top-end gaskets at the same time.

Also needed with this part

• Top-end gasket kit : see the selection
• Spark plug : see the selection
• 2-stroke oil : LIQUI MOLY 1 L 3065 · LIQUI MOLY 1 L 3063
• Air filter : see the selection

Compatibility

Check the exact model and year of your bike in the list below before ordering.

Fits:
BETA RK 6 1997
BETA ST 50 1997
BETA ST 50 1996